Specialized trailers or transportable units have long been used to process items. Such trailers or transportable units may be used to conduct livestock through a veterinary procedure or to process or sort materials. Such processes might also include the sorting or packaging of produce, the sorting of recyclable materials or even the processing of people for vaccinations. In each of these cases, the goal is to receive process items at a first end of a unit, rapidly move process items through the unit between the first end and an opposite second end and rapidly move the processed items out of the unit through an exit at the second opposite end of the unit. Such a trailer or unit must meet two basic design requirements. First, such a trailer or unit must be supported by wheels at a height sufficient to provide ground clearance for transport. Secondly, a trailer or unit must have a hitch structure for engaging a tractor vehicle. However, the rapid movement of process items into and out of a trailer is hindered when the trailer is elevated above ground level. Moreover, the forward hitch structure interferes with the placement and use of an entrance or an exit at the forward end of the trailer. This presents yet another obstacle to the rapid movement of process items through a trailer. Accordingly, design features that enhance a trailer for transportation purposes conflict with the design features that would enhance a unit intended for rapidly receiving and processing items.